1. Field of the Invention
This invention applies to a reciprocating, concrete-breaking, jack hammer type machine, especially designed to receive several varieties of shifters.
2. Description of the Prior Art
In the profession, the "shifter" is known as an element located at the lower part of a concrete breaking jack hammer, and used to hold the drill or the tool fitted in the concrete breaking machine, particularly as the assembly is lifted to pull off the tool.
There are two main types of shifters. The spring shifter consists of a resilient metal thread or wire bent in the shape of a double S. The free upper ends of the "pin" thus obtained are fitted into the holes provided on either side of the barrel of the machine. The central part of each S can rest and be locked on a pitched contact surface rigidly mounted with the barrel. Finally, the two S shapes are jointed in their lower restricted portion, to interface with a flange provided in the back of the working part of the tool. In another version, the shifter consists of a rigid lock including an offset latch in the lower portion, and which comes across the stroke of the tool flange. This lock is jointed on a spindle resting on a flange which is rigidly mounted on the body of the machine or jack hammer.
In the present state of the art, it is impossible to mount a spring type shifter on a jack hammer designed for a latch type shifter.